The present invention relates to an imaging process and apparatus for forming an image on a photosensitive media. More particularly, the imaging process is designed for use with a photosensitive media having a supportive substrate and a layer of photosensitive microcapsules on the surface thereof, and is intended to provide color correction of an image exposed on the media.
It is well known to expose a photosensitive media to light or other radiation in order to form an image in the media. In one common system for forming such exposures, an exposure beam is directed through an appropriate screen or mask which carries the image information to be reproduced. The beam is then focused onto the photosensitive media. After development of the media, the image is visibly preserved.
One photosensitive media with which this general method can be used is disclosed in commonly-assigned U.S. Pat. Nos. 4,399,209 and 4,440,846. These patents disclose a photosensitive media wherein the imaging sheet comprises a supportive substrate with a layer of microcapsules on the surface thereof. The microcapsules have an internal phase of a photohardenable photosensitive composition and a color former. The microcapsules are imagewise exposed to actinic radiation and ruptured so that the color former reacts with a developer material to produce an image.
U.S. Pat. No. 4,399,209 discloses the photosensitive media as a transfer imaging system. The imaging sheet is contacted with a receiver sheet subsequent to exposure. The receiver sheet includes a developer sheet having a support with a layer of developer material on the surface thereof. After the sheets are placed in contact, rupturing of the microcapsules is carried out.
U.S. Pat. No. 4,440,846 discloses a self-contained imaging system, wherein the imaging sheet has developer material co-deposited with the microcapsules on the sheet surface.
One goal of most imaging systems is to minimize exposure times and exposure source power requirements. The imaging materials described in the above referenced patents provide relatively low film speed when compared to silver halide systems. For the photosensitive media, film speeds on the order of 100 to 1,000 ergs/cm.sup.2 are typical.
When producing color images on the photosensitive media, it is often necessary to adjust the color balance within the finished image. This need can result from a color imbalance in the light sources used for exposure, from density variations in the masks used to present the information, or from variations in color sensitivity of the media itself. Typically, color correction is achieved by filtering within the exposure light path. However, such filtering increases the required exposure time. Color correction is achieved by reducing the amount of light received onto two colors in a three-color media to allow the third and slowest color to receive the correct amount of light.
What is needed, therefore, is an imaging system which enables color balancing of the recoded image without a significant reduction in overall exposure time.